The present invention pertains to the logic analysis art and, more particularly, to a method for emulating the response of a Boolean network control system.
The operation of an electrical circuit or system can often be described by combinational and sequential logic expressions. The mathematical expressions describing system operation may be defined by Boolean algebra, formulated in the nineteenth century by George Boole.
A particular example of a Boolean network is found in the commercial aircraft art. There, numerous monitoring systems on the aircraft provide binary status symbols representative of the condition of an airplane parameter, such as wheels up or down. These binary signals are processed in circuitry which then activates appropriate indicators or warning devices. Thus, a system might sound a warning horn if an engine throttle is retarded and the landing gear is up.
Many aircraft monitoring and indicating systems are quite complicated involving a large number of sensors, several indicators and complex logic circuitry for activating the indicators in response to the status of the sensors. It would be useful, therefore, to model such systems for the purpose of confirming proper logic operation, as well as for analysis of system faults.
Various analytical techniques have evolved for the purpose of analyzing, or modeling complex logic systems. Such techniques include Venn diagrams, truth tables and Karnough or Mahoney maps. These procedures are, however, grossly limited when more than five or six variables are considered. Each time one variable is added to an equation, the number of possible input combinations doubles. For example, a truth table with nine variables has 512 entries, whereas a truth table with 10 variables has 1,024 entries. A Mahoney or Karnough map cannot physically fit on a standard sheet of paper if more than about eight variables are involved.